Printed circuit board (PCB) is the hardware support of electronic products and an important part of signal transmission. Since the width of a golden finger (edge connector) device in the PCB is less than the width of the transmission line, the impedance of the golden finger is usually much lower than the impedance of the transmission line, which leads to impedance discontinuity, resulting in signal reflection, and seriously affecting the signal quality.
Traditionally, the reference plane below the golden finger is dug out to avoid impedance discontinuities. The impedance of the golden finger is increased in accordance with the golden finger vertical reference or horizontal reference plane being deepened, accordingly to achieve impedance matching.
However, since the reference plane below the golden finger is dug out, the impedance of the golden finger is not easy to control and the PCB thickness is inconsistent. Furthermore, since the reference plane below the golden finger is dug out, the reference plane can not wire any signals, thus area of the wiring is reduced.